Tag Archives: Bird Flu

Top U.S. chicken producing state suffers first case of bird flu

quarantine researcher checking chickens on poultry farm for bird flu

By Tom Polansek

CHICAGO (Reuters) – Georgia has confirmed its first-ever case of bird flu in commercial poultry, its agriculture department said on Monday, widening an outbreak of the disease into the United States’ biggest chicken meat-producing state.

A flock of 18,000 chickens used for breeding was culled after testing positive for H7 bird flu, according to the agriculture department. It said the birds in far northwestern Georgia were likely infected with a form of the virus that is not highly lethal because the flock did not show signs of illness.

The discovery came after officials in Alabama, Kentucky and Tennessee confirmed cases of highly pathogenic, or lethal, and low pathogenic H7N9 bird flu in breeding operations this month. U.S. officials have said the risk of the disease spreading to people from poultry or making food unsafe is low.

But the spread of highly pathogenic bird flu to poultry in new states would represent a financial risk for meat companies because it could kill more birds or require flocks to be culled. It could also trigger more import bans from other countries after South Korea and other buyers limited U.S. poultry shipments following highly pathogenic cases in Tennessee.

The worst-ever U.S. outbreak of highly pathogenic bird flu in poultry in 2014 and 2015 killed about 50 million birds, most of which were egg-laying hens in Iowa.

More than 200,000 breeding chickens in Georgia, Alabama, Tennessee and Kentucky have been killed in recent weeks by high and low pathogenic bird flu or culled to contain the virus, according to state officials. U.S. poultry producers had about 55.1 million breeder hens on hand as of March 1, according to the USDA.

In 2015, Georgia produced 7.9 billion pounds of chicken meat valued at $4.2 billion, the agency said.

“Poultry is the top sector of our number one industry, agriculture, and we are committed to protecting the livelihoods of the many farm families that are dependent on it,” Gary Black, Georgia’s agriculture commissioner, said in a statement.

Some companies are still feeling pressure related to the 2015 losses.

On Monday, Cal-Maine Foods, the biggest U.S. egg producer, said its quarterly sales fell about 32 percent from a year ago because prices were under pressure after farmers increased production in response to an outbreak two years ago.

(Reporting by Tom Polansek; Editing by Andrew Hay)

Alabama waits for U.S. verdict on bird flu; importers limit trade

By Tom Polansek

CHICAGO (Reuters) – U.S. trading partners on Friday limited shipments of poultry from Alabama, a top producer of chickens for meat, over bird flu concerns as the state’s wait for federal confirmation of two suspected cases stretched past a week.

The European Union, Kazakhstan and French Polynesia restricted shipments from Alabama counties with presumed cases of the disease, according to the U.S. Department of Agriculture’s website. The moves came a day after the state reported the agency’s national animal-health laboratories had confirmed a separate case of bird flu there.

Belarus blocked shipments from the entire state.

Alabama officials and poultry producers have been waiting since March 8 for the National Veterinary Services Laboratories (NVSL) to confirm the two suspected cases, which involve a commercial chicken farm and a backyard flock, according to the state. The facility in Ames, Iowa, is the only one in the United States that officially confirms cases of avian flu.

Swift confirmation is important for U.S. trading partners, some of which restrict shipments from geographic areas with infected flocks, and for state officials, who want to know which strain of the virus they are battling.

Highly pathogenic, or lethal, bird flu led to the deaths of about 50 million birds, mostly egg-laying hens, in the United States in 2014 and 2015.

Another widespread outbreak could be a financial blow for poultry operators, such as Tyson Foods Inc or Pilgrim’s Pride Corp, because it could kill more birds or require flocks to be culled.

The national labs must determine the strain and pathogenicity of the disease in order to officially confirm an infection, according to the USDA. The process often takes just a day.

A rapid test can be made when poultry samples contain sufficient genetic material, USDA spokeswoman Lyndsay Cole said on Thursday. But the samples from Alabama’s two suspected cases contained low levels, meaning scientists had to start a testing process that can take 14 days, she said.

Tests by a USDA-approved lab in Alabama and the national labs have already identified the H7 subtype of the virus from samples in the two suspected cases, she said.

“Our department respects the science behind the testing and is patiently waiting for accurate results,” said Amy Belcher, spokeswoman for Alabama’s agriculture department.

Alabama authorities presume the suspected cases are not highly lethal, or pathogenic, bird flu because the animals did not show signs of being sick. Still, officials have been checking birds at nearby farms for infections and the owners of the suspect flocks culled the birds, according to Alabama’s state veterinarian.

The United States must alert the World Organisation for Animal Health (OIE) if Alabama’s suspected cases are confirmed as positive, a step that could trigger more trade restrictions.

The OIE said “it is more important for the laboratory to be sure of its analysis than to be fast with it.”

(Additional reporting by Sybille de La Hamaide in Paris; Editing by Matthew Lewis)

Bird flu hits another U.S. farm that supplies Tyson Foods

quarantine researcher checking chickens on poultry farm for bird flu

By Tom Polansek

CHICAGO (Reuters) – Bird flu that is highly lethal to poultry has infected a second commercial chicken farm in Tennessee that supplies Tyson Foods Inc, company and state officials said on Thursday.

The finding expands an outbreak near the major chicken-producing states of Alabama and Georgia, and is the second in the type of breeder flock crucial for keeping the chicken-meat industry supplied with birds. A case of less dangerous bird flu was confirmed in Alabama on Thursday.

In Tennessee, authorities have started to cull the infected flock of 55,000 chickens in Lincoln County, to contain the highly pathogenic H7N9 flu, according to the U.S. Department of Agriculture.

The farm was in a quarantine zone established after authorities this month found the same strain of the disease in a flock of about 73,500 chickens less than 2 miles (3.2 km) away, the Tennessee Department of Agriculture said. That farm also supplied Tyson, the world’s biggest chicken company.

“I’m sure on the part of the company they’re quite concerned and going back and reviewing all of their information and data to determine how in the world this got into the buildings,” said Bret Marsh, state veterinarian in Indiana, which had the nation’s only highly pathogenic bird flu case in poultry in 2016.

The initial case in Tennessee was the nation’s first infection of highly pathogenic bird flu at a commercial operation in more than a year. Tennessee also recently detected a less-dangerous case of low-pathogenic flu in another chicken flock.

On Thursday, Alabama said the USDA confirmed a suspected case of low-pathogenic flu in a guinea fowl at a flea market as H7N9. Aviagen, the world’s largest poultry breeding company, has culled chickens in the state over concerns about the disease.

Highly pathogenic bird flu led to the deaths of about 50 million birds, mostly egg-laying hens, in the United States in 2014 and 2015.

Another widespread outbreak could represent a financial blow for poultry operators because it could kill more birds or require flocks to be culled. It also would likely trigger more import bans from trading partners, after South Korea, Japan and other countries limited imports after the first highly pathogenic case in Tennessee.

China has also been grappling with an outbreak of H7N9, which has killed 161 people since October. U.S. authorities have said that strain is genetically distinct from the H7N9 in Tennessee and that the risk of the disease spreading to people from poultry or making food unsafe is low.

Tyson said it worked with Tennessee and federal officials to quickly euthanize birds in the infected flock and did not expect disruptions to its chicken supply.

“Our business is diversified and scaled across multiple states, so we plan to meet our customers’ needs,” spokesman Worth Sparkman said.

Tyson shares fell 1.7 percent to close at $62.00 on Thursday.

The company has said it tests all the birds it owns for the virus and flocks diagnosed with highly pathogenic flu are not processed.

Wild birds can carry the disease without showing signs of sickness and transmit it to poultry through feces, feathers or other forms of contract.

(Editing by Chizu Nomiyama and Matthew Lewis)

Poultry breeder Aviagen culls U.S. flock over bird flu fears

FILE PHOTO: The Avian influenza virus is harvested from a chicken egg as part of a diagnostic process in this undated U.S. Department of Agriculture (USDA) handout image. Erica Spackman/USDA/Handout/File Photo via REUTERS

By Tom Polansek

CHICAGO (Reuters) – Aviagen [EWESJA.UL], the world’s leading poultry breeding company, has euthanized chickens at a farm in Alabama over concerns about bird flu, the company said on Tuesday, as likely cases of the disease emerged in a top chicken-producing state.

Alabama officials said they suspected that poultry at three sites in the state were infected with the virus, about a week after some 90,500 chickens were culled over infections at two commercial operations across the border in Tennessee.

Aviagen detected the presence of antibodies for the flu virus in a flock in Alabama that showed “no evidence of clinical disease,” company spokeswoman Marla Robinson said in an email. The company is based in Alabama.

The company euthanized the flock and “all eggs which were collected from that farm in the production system were traced and removed,” she said. Aviagen did not respond to a question about how many birds were killed.

Tony Frazier, Alabama’s state veterinarian, said the company chose to cull about 15,000 birds. The U.S. Department of Agriculture (USDA) said the farm had 153,000 birds.

A national USDA lab is testing samples from poultry in Alabama to identify the strain of the virus and how lethal it is for birds, after another agency-approved lab identified the H7 subtype of the disease in samples, USDA spokeswoman Lyndsay Cole said.

The birds in Alabama did not show clinical signs of sickness, which indicates they did not have a highly lethal, or pathogenic, form of the virus, Cole said.

In Tennessee, both cases were identified as H7N9. The USDA on March 5 confirmed that one was the United States’ first infection of highly pathogenic flu in commercial poultry in a year. Days later, the state said it had found the other case nearby and it was low pathogenic.

Highly pathogenic bird flu led to the deaths of about 50 million birds, mostly egg-laying hens, in the United States in 2014 and 2015.

Another highly pathogenic outbreak would likely represent a financial blow for poultry operators such as Tyson Foods Inc and Pilgrim’s Pride Corp because it would kill more birds or require flocks to be culled.

It also would likely trigger more import bans from trading partners, after South Korea, Japan and other countries limited imports after the highly pathogenic case in Tennessee.

Health officials have said the risk of bird flu spreading to people from poultry or making food unsafe was low.

Separately, Frazier said the owner of a backyard flock suspected of having the virus chose to cull about 70 birds. No poultry linked to the third suspected case, which involved birds at a flea market, have been culled, he said.

Frazier said the cases were still only suspected flu infections and needed to be confirmed by the USDA. Earlier, the Alabama Department of Agriculture and Industries called a news conference to discuss what it said were three findings of avian influenza.

Alabama raised more than 1 billion chickens for meat in 2015, making it the country’s third largest producer, according to the USDA.

The national USDA laboratory, to which samples from the state were sent, is the only one in the United States that officially confirms cases.

The World Organization for Animal Health requires that all confirmed low-pathogenic H5 and H7 bird flu subtypes be reported because of their potential to mutate into highly pathogenic strains. Highly pathogenic cases also must be reported.

(Reporting by Tom Polansek; Editing by Frances Kerry, Toni Reinhold)

Bird flu infects Alabama poultry, likely low pathogenic -officials

By Tom Polansek

CHICAGO (Reuters) – Bird flu has infected poultry at three sites in northern Alabama shortly after being found at two farms in neighboring Tennessee, and more chickens have been culled to contain the virus, state and industry officials in Alabama said on Tuesday.

The cases in Alabama are suspected to be the less dangerous form of the disease, known as low pathogenic, because the infected flocks did not have high levels of mortality, said Ray Hilburn, associate director of the Alabama Poultry and Egg Association, an industry group.

The flocks were near the spot in southern Tennessee where the U.S. Department of Agriculture confirmed on March 5 the nation’s first case of highly pathogenic flu in commercial poultry in more than a year. Days later, Tennessee said it had detected low-pathogenic flu at another chicken farm nearby.

Highly pathogenic bird flu is often fatal for domesticated poultry and led to the deaths of about 50 million birds, mostly egg-laying hens, in the United States in 2014 and 2015. The less-serious low pathogenic flu form can cause coughing, depression and other symptoms in birds.

The spread of highly pathogenic flu could represent a financial blow for poultry operators such as Tyson Foods Inc and Pilgrim’s Pride Corp because it would kill more birds or require flocks to be culled. It also would trigger more import bans from other countries, after South Korea, Japan and other nations limited imports following the highly pathogenic case in Tennessee.

Alabama has not received any definitive test results that show its cases are highly pathogenic, said Amy Belcher, spokeswoman for the Alabama Department of Agriculture and Industries. No epidemiological connections have been made between the cases in Tennessee and Alabama, she added.

Belcher declined to discuss culling of the birds ahead of a news conference on bird flu, or avian influenza (AI), in the state on Tuesday.

Hilburn said infected birds had been culled but did not know how many. He said one case in Alabama was at a commercial breeding facility for chickens raised for meat and one involved a backyard flock.

“As soon as they find out that its possibly any type of AI, they’re going to get rid of the birds,” Hilburn said. “They don’t take a chance on anything.”

Health officials have said the risk of bird flu spreading to people from poultry or making food unsafe was low.

(Reporting by Tom Polansek; Editing by Chizu Nomiyama and Frances Kerry)

Bird flu strikes Tennessee chickens again, in a less-dangerous form

The Avian influenza virus is harvested from a chicken egg as part of a diagnostic process in this undated U.S. Department of Agriculture (USDA) handout image. REUTERS / Erica Spackman / USDA / Handout via Reuters

By Tom Polansek

CHICAGO (Reuters) – A commercial flock of 17,000 chickens in Tennessee has been culled after becoming infected with low-pathogenic bird flu, state agricultural officials said on Thursday, days after a more dangerous form of the disease killed poultry in a neighboring county.

Authorities killed and buried chickens at the site in Giles County, Tennessee, “as a precaution” after a case of highly pathogenic flu in Lincoln County led to the deaths of about 73,500 chickens over the weekend, according to the Tennessee Department of Agriculture. It said officials did not believe birds at one premise sickened those at the other.

Highly pathogenic bird flu is often fatal for domesticated poultry and led to the deaths of about 50 million birds, mostly egg-laying hens, in the United States in 2014 and 2015. Low-pathogenic flu is less serious and can cause coughing, depression and other symptoms in birds.

The highly pathogenic case in Tennessee was the first such infection in a commercial U.S. operation in more than a year and heightened fears among chicken producers that the disease may return.

The spread of highly pathogenic flu could represent a financial blow for poultry operators, such as Tyson Foods Inc and Pilgrim’s Pride Corp, because it would kill more birds or require flocks to be culled. It also would trigger more import bans from other countries, after South Korea, Japan and other nations limited imports because of the case in Lincoln County.

Jack Shere, chief veterinary officer for the U.S. Department of Agriculture, said in an interview that there was speculation the highly pathogenic virus found in Tennessee shared similar characteristics with a low-pathogenic virus that circulated in Tennessee, Kentucky, Minnesota and Illinois in 2009.

Wild migratory birds can carry the flu without showing symptoms and spread it to poultry through feces, feathers or other contact.

“This virus can mutate very easily, so low-pathogenic issues are just as important – when they are circulating among the wild birds – as the high-pathogenic issues,” Shere said.

Both cases in Tennessee were located along the state’s southern border with Alabama, one of the country’s top producers of “broiler” chickens for meat. They also were both in facilities for chickens that bred broiler birds and involved the same strain, H7N9, according to Tennessee’s agriculture department.

The state said it was testing poultry within a 10-kilometer radius of the Giles County site for the flu and so far had not found any other sick flocks.

“When routine testing showed a problem at this facility, the operators immediately took action and notified our lab,” said Charles Hatcher, Tennessee’s state veterinarian.

H7N9 is the same name as a strain of the virus that has killed people in China, but U.S. authorities said the Tennessee virus was genetically distinct.

U.S. officials have said the risk of bird flu spreading to people from poultry or making food unsafe was low.

Low-pathogenic bird flu also was recently detected on a turkey farm in Wisconsin. Authorities there decided to keep the birds under quarantine until they tested negative for the virus, rather than to cull them, according to the state.

(Additional reporting by Mark Weinraub in Washington, D.C.; Editing by G Crosse, Richard Chang and Bernard Orr)

Bird flu found in Tennessee chicken flock on Tyson-contracted farm

The Avian influenza virus is harvested from a chicken egg as part of a diagnostic process in this undated U.S. Department of Agriculture

By Jo Winterbottom

(Reuters) – A strain of bird flu has been detected in a chicken breeder flock on a Tennessee farm contracted to U.S. food giant Tyson Foods Inc, and the 73,500 birds will be culled to stop the virus from entering the food system, government and company officials said on Sunday.

The U.S. Department of Agriculture said this represented the first confirmed case of highly pathogenic H7 avian influenza (HPAI) in commercial poultry in the United States this year. It is the first time HPAI has been found in Tennessee, the state government said.

Tyson, the biggest chicken meat producer in the United States, said in a statement it was working with Tennessee and federal officials to contain the virus by euthanizing the birds on the contract farm.

In 2014 and 2015, during a widespread outbreak of HPAI, the United States killed nearly 50 million birds, mostly egg-laying hens. The losses pushed U.S. egg prices to record highs and prompted trading partners to ban imports of American poultry, even though there was little infection then in the broiler industry.

No people were affected in that outbreak, which was primarily of the H5N2 strain. The risk of human infection in poultry outbreaks is low, although in China people have died this winter amid an outbreak of the H7N9 virus in birds.

The facility in Tennessee’s Lincoln County has been placed under quarantine, along with approximately 30 other poultry farms within a 6.2-mile (10 km) radius of the site, the state said. Other flocks in the quarantined area are being tested, it added.

Tyson, the USDA and the state did not name the facility involved. Tyson said that it did not expect disruptions to its chicken business.

The USDA should have more information by Monday evening about the particular strain of the virus involved, spokeswoman Donna Karlsons said by email.

HPAI bird flu was last found in a commercial turkey flock in Indiana in January 2016.

The USDA said it would inform the World Organization for Animal Health (OIE) and international trading partners of the outbreak.

The biggest traditional markets for U.S. chicken meat are Mexico and Canada, which introduced state or regional bans on U.S. broiler exports after the outbreak two years ago, and China, which imposed a national ban.

Tennessee’s broiler production is too small to rank it in the top five U.S. producing states but it is the third-largest generator of cash receipts in agriculture for the state.

In January, the USDA detected bird flu in a wild duck in Montana that appeared to match one of the strains found during the 2014 and 2015 outbreak.

The United States stepped up biosecurity measures aimed at preventing the spread of bird flu after the outbreak two years ago.

Tyson said precautions being taken include disinfecting all vehicles entering farms and banning all nonessential visitor access to contract farms.

In recent months, different strains of bird flu have been confirmed across Asia and in Europe. Authorities have culled millions of birds in affected areas to control the outbreaks.

France, which has the largest poultry flock in the European Union, has reported outbreaks of the highly contagious H5N8 bird flu virus. In South Korea, the rapid spread of the H5N6 strain of the virus has led to the country’s worst-ever outbreak of bird flu.

(Reporting by Lewis Krauskopf in New York and Jo Winterbottom in Chicago; Editing by Will Dunham)

U.S. reports low pathogenic bird flu outbreak in Wisconsin: OIE

PARIS (Reuters) – The United States reported an outbreak of avian flu on a farm in Wisconsin, the second in the country in less than a week although the virus found this time is considered less virulent, the World Organisation for Animal Health (OIE) said on Tuesday.

A strain of low pathogenic H5N2 avian flu has been discovered in a flock of 84,000 turkeys in Barron County, Wisconsin, the U.S. Department of Agriculture (USDA) said in a report posted on the website of the Paris-based OIE.

The USDA said the turkey flock was tested after birds showed signs of depression and the infected premises were quarantined.

The new outbreak comes after the detection of highly pathogenic H7 bird flu last week in a chicken breeder flock in Tennessee farm contracted by U.S. food giant Tyson Foods Inc.

As opposed to highly pathogenic strains which can cause high mortality rates among poultry, low pathogenic ones typically cause few or no clinical signs in birds.

In 2014 and 2015, during a widespread outbreak of highly pathogenic avian flu, primarily of the H5N2 strain, the United States killed nearly 50 million birds, mostly egg-laying hens. The losses pushed U.S. egg prices to record highs.

The USDA said tests had shown that the H5N2 virus detected in Wisconsin was of North American wild bird origin and distinct from the H5N2 viruses found in 2015.

The risk of human infection in poultry outbreaks is low, although in China more than 110 people died this winter amid an outbreak of the H7N9 virus in birds.

The detection of a first case of bird flu in the United States this year prompted several Asian countries, including South Korea, Japan, Taiwan and Hong Kong, to limit imports of U.S. poultry.

(Reporting by Sybille de La Hamaide and Gus Trompiz, editing by David Evans)

Hard to detect, China bird flu virus may be more widespread

quarantine researcher checking chickens on poultry farm for bird flu

By Dominique Patton

BEIJING (Reuters) – Bird flu infection rates on Chinese poultry farm

BEIJING (Reuters) – Bird flu infection rates on Chinese poultry farms may be far higher than previously thought, because the strain of the deadly virus that has killed more than 100 people this winter is hard to detect in chickens and geese, animal health experts say.

s may be far higher than previously thought, because the strain of the deadly virus that has killed more than 100 people this winter is hard to detect in chickens and geese, animal health experts say.

Poultry that have contracted the H7N9 strain of the avian flu virus show little or no sign of symptoms. That means any infection is only likely to be detected if farmers or health authorities carry out random tests on a flock, the experts said.

But in humans, it can be deadly.

That’s different to other strains, such as the highly pathogenic H5N6 that struck South Korean farms in December, prompting the government to call in the army to help cull some 26 million birds.

But that strain didn’t kill any people.

There have been multiple outbreaks of bird flu around the world in recent months, with at least half a dozen different strains circulating. The scale of the outbreaks and range of viral strains increases the chances of viruses mixing and mutating, with new versions that can spread more easily between people, experts say.

For now, H7N9 is thought to be relatively difficult to spread between people. China’s Center for Disease Control and Prevention has said the vast majority of people infected by H7N9 reported exposure to poultry, especially at live markets.

“There are very few, if any, clinical signs when this (H7N9) virus infects birds, and that’s the main reason we’re not seeing reporting coming from poultry farms in China,” said Matthew Stone, deputy director general for International Standards and Science at the World Organisation for Animal Health (OIE).

INTENSIVE OUTBREAK

As many as 79 people died from H7N9 bird flu in China in January alone, up to four times higher than the same month in past years.

While spikes in contamination rates are normal in January – the main influenza season – the high level of human infections has prompted fears the spread of the virus among people could be the highest on record – especially as the number of bird flu cases reported by farmers has been conspicuously low.

The high number of human infections points to a significant outbreak in the poultry population that is not being detected, says Guan Yi, director of the State Key Laboratory of Emerging Infectious Diseases and the Center of Influenza Research at the University of Hong Kong.

“If we have so many human infections, naturally it reflects activity, an intensive outbreak in chickens. They are highly associated,” he said.

China has the world’s largest flock of chickens, ducks and geese, and slaughtered more than 11 billion birds for meat in 2014, according to the United Nations’ Food and Agriculture Organisation (FAO).

The last major bird flu outbreak in China, in 2013, killed 36 people and cost the farming industry around $6.5 billion.

CONTROL CHALLENGE

The experts’ assessment underscores the challenge for China’s government and health ministry in monitoring and controlling the H7N9 outbreak in both people and poultry.

While, with few visible signs of infection in birds, it’s easier for farmers to flout the reporting rules and continue selling poultry at market, Stone at the OIE said China has a “very significant” surveillance program at live markets.

The government promised on Thursday to tighten controls on markets and poultry transport to help battle the virus.

The agriculture ministry last month collected more than 102,000 serum samples and 55,000 virological samples from birds in 26 provinces. Of the latter samples, only 26 tested positive for the virus, according to data on the ministry’s website.

But the rapid rise in human infections and spread to a wider geographic area is likely to increase pressure on Beijing to do more poultry testing at markets and on farms.

The ministry did not respond to faxed questions on its surveillance efforts.

The National Health and Family Planning Commission said on Thursday the spread of H7N9 among people was slowing.

Some Chinese netizens have called for more timely reports on infections, and some experts have said China has been slow to respond to the human outbreak. The authorities have warned the public to stay alert for the virus, cautioning against panic.

Others played down the threat to humans, as long as they stay away from live markets.

“As scientists, we should be watching this outbreak and the effectiveness of any control measures,” said Ian Mackay, a virologist and associate professor at the University of Queensland in Australia. “We don’t have a vaccine available for H7N9 in humans, but we do have effective antivirals.”

“So far, the virus does not spread well between humans,” he added. “As members of the public, who do not seek out live poultry from markets in China, we have almost nothing to worry about from H7N9 right now.”

(Reporting by Dominique Patton in BEIJING, with additional reporting by Ben Hirschler in LONDON; Editing by Josephine Mason and Ian Geoghegan)

Proliferation of bird flu outbreaks raises risk of human pandemic

wokers gather ducks that may have bird flu

By Kate Kelland

LONDON (Reuters) – The global spread of bird flu and the number of viral strains currently circulating and causing infections have reached unprecedented levels, raising the risk of a potential human outbreak, according to disease experts.

Multiple outbreaks have been reported in poultry farms and wild flocks across Europe, Africa and Asia in the past three months. While most involve strains that are currently low risk for human health, the sheer number of different types, and their presence in so many parts of the world at the same time, increases the risk of viruses mixing and mutating – and possibly jumping to people.

“This is a fundamental change in the natural history of influenza viruses,” Michael Osterholm, an infectious disease specialist at University of Minnesota, said of the proliferation of bird flu in terms of geography and strains – a situation he described as “unprecedented”.

Global health officials are worried another strain could make a jump into humans, like H5N1 did in the late 1990s. It has since caused hundreds of human infections and deaths, but has not acquired the ability to transmit easily from person to person.

The greatest fear is that a deadly strain of avian flu could then mutate into a pandemic form that can be passed easily between people – something that has not yet been seen.

While avian flu has been a prominent public health issue since the 1990s, ongoing outbreaks have never been so widely spread around the world – something infectious disease experts put down to greater resilience of strains currently circulating, rather than improved detection or reporting.

While there would normally be around two or three bird flu strains recorded in birds at any one time, now there are at least half a dozen, including H5N1, H5N2, H5N8 and H7N8.

The Organization for Animal Health (OIE) says the concurrent outbreaks in birds in recent months are “a global public health concern”, and the World Health Organization’s director-general warned this week the world “cannot afford to miss the early signals” of a possible human flu pandemic.

The precise reasons for the unusually large number and sustained nature of bird outbreaks in recent months, and the proliferation of strains, is unclear – although such developments compound the global spreading process.

Bird flu is usually spread through flocks through direct contact with an infected bird. But Osterholm said wild birds could be “shedding” more of the virus in droppings and other secretions, increasing infection risks. He added that there now appears to be “aerosol transmission from one infected barn to others, in some cases many miles away”.

Ian MacKay, a virologist at Australia’s University of Queensland, said the current proliferation of strains means that “by definition, there is an increased risk” to humans.

“You’ve got more exposures, to more farmers, more often, and in greater numbers, in more parts of the world – so there has to be an increased risk of spillover human cases,” he told Reuters.

BRITAIN TO BANGLADESH

Nearly 40 countries have reported new outbreaks of highly pathogenic avian influenza in poultry or wild birds since November, according to the WHO.

In China, H7N9 strains of bird flu have been infecting both birds and people, with the of human cases rising in recent weeks due to the peak of the flu season there. According to the WHO, more than 900 people have been infected with H7N9 bird flu since it emerged in early 2013.

In birds, latest data from the OIE should that outbreaks of highly pathogenic avian flu have been detected in Britain, Italy, Kuwait and Bangladesh in the last few days alone.

Russia’s agriculture watchdog issued a statement describing the situation as “extremely tense” as it reported H5N8 flu outbreaks in another four regions. Hungarian farmers have had to cull 3 million birds, mostly geese and ducks.

These come on top of epidemics across Europe and Asia which have been ongoing since late last year, leading to mass culling of poultry in many countries.

Strains currently documented as circulating in birds include H5N8 in many parts of Europe as well as in Kuwait, Egypt and elsewhere, and H5N1 in Bangladesh and India.

In Africa – which experts say is especially vulnerable to missing flu outbreak warning signs due to limited local government capacities and weak animal and human health services – H5N1 outbreaks have been reported in birds in Burkina Faso, Cameroon, Ghana, Niger, Nigeria and Togo. H5N8 has been detected in Tunisia and Egypt, and H7N1 in Algeria.

The United States has, so far this year, largely escaped bird flu, but is on high alert after outbreaks of H5N2, a highly pathogenic bird flu, hit farms in 15 states in 2015 and led to the culling of more than 43 million poultry.

David Nabarro, a former senior WHO official who has also served as U.N. system senior coordinator for avian and human influenza, says the situation is worrying. “For me the threat from avian influenza is the most serious (to public health), because you never know when,” he told Reuters in Geneva.

HIGHLY PATHOGENIC H5N1

H5N1 is under close surveillance by health authorities around the world. It has long been seen as one to watch, feared by infectious disease experts because of its pandemic potential if it were to mutate an acquire human-to-human transmission capability.

A highly pathogenic virus, it jumped into humans in Hong Kong in 1997 and then re-emerged in 2003/2004, spreading from Asia to Europe and Africa. It has caused hundreds of infections and deaths in people and prompted the culling of hundreds of millions of poultry.

Osterholm noted that some currently circulating H5 strains – including distant relatives of H5N1 – are showing significant capabilities for sustaining their spread between wild flocks and poultry, from region to region and farm to farm.

“What we’re learning about H5 is, that whether its H5N6, H5N8, H5N2 or H5N5, this is a very dangerous bird virus.”

Against that background, global health authorities and infectious disease experts want awareness, surveillance and vigilance stepped up.

Wherever wild birds are found to be infected, they say, and wherever there are farms or smallholdings with affected poultry or aquatic bird flocks, regular, repeated and consistent testing of everyone and anyone who comes into contact is vital.

“Influenza is a very tough beast because it changes all the time, so the ones we’re tracking may not include one that suddenly emerges and takes hold,” said MacKay.

“Right now, it’s hard to say whether we’re doing enough (to keep on top of the threat). I guess that while it isn’t taking off, we seem to be doing enough.”

(Additional reporting by Ed Stoddard in Johannesburg, Stephanie Nebehay in Geneva, Polina Devitt in Moscow and Sybille de La Hamaide in Paris; Editing by Pravin Char)